Wide-angle zoom lens system

Claim 2

A wide-angle zoom lens system comprising a front lens group comprising a first negative meniscus lens component having a convex surface on the object side, a second negative lens component and a third positive lens component, and a rear lens group comprising a fourth positive lens component, a fifth positive meniscus lens component having a convex surface on the object side, a sixth negative lens component and a seventh positive lens component; said lens system being so adapted as to permit changing focal length of the entire lens system as a whole by varying the airspace reserved between said front and rear lens groups and satisfy the conditions enumerated below: (1) 1.68<n 1 , n 2 (2) n 4 , n 5 <1.65 (3) 1.75<n 6 ##EQU3## (5) 1.6<|r 6 |/f wherein the reference symbols n 1 , n 2 , n 4 , n 5 and n 6 represent refractive indices of the first, second, fourth, fifth and sixth lens components respectively, the reference symbols d 1 and d 3 designate thicknesses of the first and second lens components respectively, the reference symbol d 2 denotes the airspace reserved between the first and second lens components, the reference symbol r 6 represents radius of curvature on the image side surface of the third lens component and the reference symbol f designates focal length of the entire lens system as a whole at the wide position.

Claim 3

A wide-angle zoom lens system according to claim 1 so adapted as to satisfy the additional conditions enumerated below: ##EQU4## (7) n 7 <1.65 (8) 0.6<r 9 /f<0.83 (9) 1<r 4 /r 5 <2.4 wherein the reference symbols d 7 , d 9 and d 11 represent thicknesses of the fourth, fifth and sixth lens components respectively, the reference symbol n 7 designates refractive index of the seventh lens component, and the reference symbols r 4 , r 5 and r 9 denote radii of curvature on the image side surface of the second lens component, the object side surface of the third lens component and the object side surface of the fifth lens component.

Claim 4

A wide-angle zoom lens system according to claim 1 having the following numerical data: ______________________________________ f = 1 2ω = 73.4° ______________________________________ r.sub.1 = 1.7061 d.sub.1 = 0.134 n.sub.1 = 1.80610 ν.sub.1 = 40.95 r.sub.2 = 0.6154 d.sub.2 = 0.284 r.sub.3 = -2.1733 d.sub.3 = 0.138 n.sub.2 = 1.80610 ν.sub.2 = 40.95 r.sub.4 = 2.2662 d.sub.4 = 0.025 r.sub.5 = 1.3015 d.sub.5 = 0.155 n.sub.3 = 1.72342 ν.sub.3 = 37.95 r.sub.6 = -2.9799 d.sub.6 = 0.034 ˜ 0.772 r.sub.7 = 1.4473 d.sub.7 = 0.306 n.sub.4 = 1.62012 ν.sub.4 = 49.66 r.sub.8 = -2.3949 d.sub.8 = 0.014 r.sub.9 = 0.6876 d.sub.9 = 0.123 n.sub.5 = 1.62374 ν.sub.5 = 47.10 r.sub.10 = 2.3736 d.sub.10 = 0.116 r.sub.11 = -1.7497 d.sub.11 = 0.173 n.sub.6 = 1.78470 ν.sub.6 = 26.22 r.sub.12 = 0.7017 d.sub.12 = 0.052 r.sub.13 = 7.1837 d.sub.13 = 0.069 n.sub.7 = 1.61340 ν.sub.7 = 43.84 r.sub.14 = -0.7438 f.sub.I = -1.633 f.sub.II = 1.182 f.sub.BW = 1.329 ______________________________________ wherein the reference symbols r 1 through r 14 represent radii of curvature on the surfaces of the respective lens components, the reference symbols d 1 through d 13 designate thicknesses of the respective lens components and the airspaces reserved therebetween, the reference symbols n 1 through n 7 denote refractive indices of the respective lens components, the reference symbols ν 1 through ν 7 represent Abbe's numbers of the respective lens components, the reference symbol f I designates focal length of the front lens group, the reference symbol f II denotes focal length of the rear lens group, the reference symbol 2ω represents angle of field and the reference symbol f BW designates back focal length at the wide position.

Claim 5

A wide-angle zoom lens system according to claim 1 having the following numerical data: ______________________________________ f = 1 2ω = 73.4° ______________________________________ r.sub.1 = 2.0924 d.sub.1 = 0.152 n.sub.1 = 1.74400 ν.sub.1 = 44.73 r.sub.2 = 0.6377 d.sub.2 = 0.250 r.sub.3 = -2.4324 d.sub.3 = 0.172 n.sub.2 = 1.73400 ν.sub.2 = 51.45 r.sub.4 = 1.6607 d.sub.4 = 0.040 r.sub.5 = 1.2417 d.sub.5 = 0.155 n.sub.3 = 1.72342 ν.sub.3 = 37.95 r.sub.6 = -3.4749 d.sub.6 = 0.034 ˜ 0.761 r.sub.7 = 1.6372 d.sub.7 = 0.196 n.sub.4 = 1.62330 ν.sub.4 = 53.20 r.sub.8 = -1.9165 d.sub.8 = 0.0139 r.sub.9 = 0.7335 d.sub.9 = 0.101 n.sub.5 = 1.62299 ν.sub.5 = 58.14 r.sub.10 = 3.2318 d.sub.10 = 0.101 r.sub.11 = -1.6623 d.sub.11 = 0.287 n.sub.6 = 1.78470 ν.sub.6 = 26.22 r.sub.12 = 0.7394 d.sub.12 = 0.052 r.sub.13 = -17.2781 d.sub.13 = 0.069 n.sub.7 = 1.61340 ν.sub.7 = 43.84 r.sub.14 = -0.6832 f.sub.I = -1.633 f.sub.II = 1.182 f.sub.BW = 1.339 ______________________________________ wherein the reference symbols r 1 through r 14 represent radii of curvature on the surfaces of the respective lens components, the reference symbols d 1 through d 13 designate thicknesses of the respective lens components and the airspaces reserved therebetween, the reference symbols n 1 through n 7 denote refractive indices of the respective lens components, the reference symbols ν 1 through ν 7 represents Abbe's numbers of the respective lens components, the reference symbol f I designates focal length of the front lens group, the reference symbol f II denotes focal length of the rear lens group, the reference symbol 2ω represents angle of field and the reference symbol f BW designates back focal length at the wide position.

Claim 6

A wide-angle zoom lens system according to claim 1 having the following numerical data: ______________________________________ f = 1 2ω = 73.4° ______________________________________ r.sub.1 = 1.7925 d.sub.1 = 0.134 n.sub.1 = 1.79952 ν.sub.1 = 42.24 r.sub.2 = 0.6226 d.sub.2 = 0.289 r.sub.3 = -2.2268 d.sub.3 = 0.138 n.sub.2 = 1.79952 ν.sub.2 = 42.24 r.sub.4 = 2.2176 d.sub.4 = 0.026 r.sub.5 = 1.3072 d.sub.5 = 0.155 n.sub.3 = 1.72342 ν.sub.3 = 37.95 r.sub.6 = -3.0081 d.sub.6 = 0.034 ˜ 0.739 r.sub.7 = 1.4045 d.sub.7 = 0.307 n.sub.4 = 1.62012 ν.sub.4 = 49.66 r.sub.8 = -2.5521 d.sub.8 = 0.014 r.sub.9 = 0.7186 d.sub.9 = 0.123 n.sub.5 = 1.63303 ν.sub.5 = 47.10 r.sub.10 = 2.8869 d.sub.10 = 0.120 r.sub.11 = -1.5473 d.sub.11 = 0.172 n.sub.6 = 1.80603 ν.sub.6 = 26.22 r.sub.12 = 0.7323 d.sub.12 = 0.052 r.sub.13 = 12.8440 d.sub.13 = 0.069 n.sub.7 = 1.63930 ν.sub.7 = 44.88 r.sub.14 = -0.7237 f.sub.I = -1.633 f.sub.II = 1.182 f.sub.BW = 1.332 ______________________________________ wherein the reference symbols r 1 through r 14 represent radii of curvature on the surfaces of the respective lens components, the reference symbols d 1 through d 13 designate thicknesses of the respective lens components and the airspaces reserved therebetween, the reference symbols n 1 through n 7 denote refractive indices of the respective lens components, the reference symbols ν 1 through ν 7 represent Abbe's numbers of the respective lens components, the reference symbol f I designates focal length of the front lens group, the reference symbol f II denotes focal length of the rear lens group, the reference symbol 2ω represents angle of field and the reference symbol f BW designates back focal length at the wide position.

Claim 7

A wide-angle zoom lens system according to claim 1 having the following numerical data: ______________________________________ f = 1 2ω = 73.4° ______________________________________ r.sub.1 = 1.7093 d.sub.1 = 0.152 n.sub.1 = 1.78590 ν.sub.1 = 44.18 r.sub.2 = 0.6094 d.sub.2 = 0.255 r.sub.3 = -1.8798 d.sub.3 = 0.155 n.sub.2 = 1.75700 ν.sub.2 = 47.87 r.sub.4 = 1.9607 d.sub.4 = 0.034 r.sub.5 = 1.3051 d.sub.5 = 0.155 n.sub.3 = 1.72342 ν.sub.3 = 37.95 r.sub.6 = -2.6389 d.sub.6 = 0.034 ˜ 0.765 r.sub.7 = 1.5830 d.sub.7 = 0.209 n.sub.4 = 1.62230 ν.sub.4 = 53.20 r.sub.8 = -1.9994 d.sub.8 = 0.014 r.sub.9 = 0.729 d.sub.9 = 0.101 n.sub.5 = 1.62280 ν.sub.5 = 57.06 r.sub.10 = 3.0318 d.sub.10 = 0.089 r.sub.11 = -1.8134 d.sub.11 = 0.292 n.sub.6 = 1.78472 ν.sub.6 = 25.71 r.sub.12 = 0.7306 d.sub.12 = 0.052 r.sub.13 = -33.3245 d.sub.13 = 0.069 n.sub.7 = 1.62606 ν.sub.7 = 39.10 r.sub.14 = -0.7187 f.sub.I = -1.633 f.sub.II = 1.182 f.sub.BW = 1.347 ______________________________________ wherein the reference symbols r 1 through r 14 represent radii of curvature on the surfaces of the respective lens components, the reference symbols d 1 through d 13 designate thicknesses of the respective lens components and the airspaces reserved therebetween, the reference symbols n 1 through n 7 denote refractive indices of the respective lens components, the reference symbols ν 1 through ν 7 represent Abbe's numbers of the respective lens components, the reference symbol f I designates focal length of the front lens group, the reference symbol f II denotes focal length of the rear lens group, the reference symbol 2ω represents angle of field and the reference symbol f BW designates back focal length at the wide position.

Claim 8

A wide-angle zoom lens system according to claim 1 having the following numerical data: ______________________________________ f = 1 2ω = 73.4° ______________________________________ r.sub.1 = 2.9317 d.sub.1 = 0.153 n.sub.1 = 1.72342 ν.sub.1 = 37.95 r.sub.2 = 0.7299 d.sub.2 = 0.322 r.sub.3 = 32.6868 d.sub.3 = 0.117 n.sub.2 = 1.69680 ν.sub.2 = 55.52 r.sub.4 = 1.1632 d.sub.4 = 0.050 r.sub.5 = 1.0146 d.sub.5 = 0.369 n.sub.3 = 1.62606 ν.sub.3 = 39.10 r.sub.6 = -51.3765 d.sub.6 = 0.034 ˜ 0.762 r.sub.7 = 1.5164 d.sub.7 = 0.112 n.sub.4 = 1.62230 ν.sub.4 = 53.20 r.sub.8 = -1.8000 d.sub.8 = 0.014 r.sub.9 = 0.6930 d.sub.9 = 0.095 n.sub.5 = 1.62230 ν.sub.5 = 53.20 r.sub.10 = 2.1325 d.sub.10 = 0.142 r.sub.11 = -1.6898 d.sub.11 = 0.238 n.sub.6 = 1.78472 ν.sub.6 = 25.71 r.sub.12 = 0.7082 d.sub.12 = 0.057 r.sub.13 = -6.1833 d.sub.13 = 0.044 n.sub.7 = 1.62230 ν.sub.7 = 53.20 r.sub.14 = -0.6951 f.sub.I = -1.632 f.sub.II = 1.182 f.sub.BW = 1.311 ______________________________________ wherein the reference symbols r 1 through r 14 represent radii of curvature on the surfaces of the respective lens components, the reference symbols d 1 through d 13 designate thicknesses of the respective lens components and the airspaces reserved therebetween, the reference symbols n 1 through n 7 denote refractive indices of the respective lens components, the reference symbols ν 1 through ν 7 represent Abbe's numbers of the respective lens components, the reference symbol f I designates focal length of the front lens group, the reference symbol f II denotes focal length of the rear lens group, the reference symbol 2ω represents angle of field and the reference symbol f BW designates back focal length at the wide position.

Claim 9

A wide-angle zoom lens system according to claim 1 having the following numerical data: ______________________________________ f = 1 2ω = 73.4° ______________________________________ r.sub.1 = 1.5283 d.sub.1 = 0.134 n.sub.1 = 1.80440 ν.sub.1 = 39.62 r.sub.2 = 0.5803 d.sub.2 = 0.284 r.sub.3 = -1.8201 d.sub.3 = 0.138 n.sub.2 = 1.79952 ν.sub.2 = 42.24 r.sub.4 = 2.4626 d.sub.4 = 0.009 r.sub.5 = 1.2637 d.sub.5 = 0.172 n.sub.3 = 1.72342 ν.sub.3 = 37.95 r.sub.6 = -2.6175 d.sub.6 = 0.034 ˜ 0.775 r.sub.7 = 1.9581 d.sub.7 = 0.140 n.sub.4 = 1.61484 ν.sub.4 = 51.17 r.sub.8 = -2.5071 d.sub.8 = 0.014 r.sub.9 = 0.7430 d.sub. 9 = 0.171 n.sub.5 = 1.62374 ν.sub.5 = 47.10 r.sub.10 = 3.2331 d.sub.10 = 0.175 r.sub.11 = -1.2705 d.sub.11 = 0.123 n.sub.6 = 1.79177 ν.sub.6 = 26.22 r.sub.12 = 0.7735 d.sub.12 = 0.052 r.sub.13 = 3.6029 d.sub.13 = 0.069 n.sub.7 = 1.64268 ν.sub.7 = 44.88 r.sub.14 = -0.693 f.sub.I = -1.633 f.sub.II = 1.182 f.sub.BW = 1.343 ______________________________________ wherein the reference symbols r 1 through r 14 represent radii of curvature on the surfaces of the respective lens components, the reference symbols d 1 through d 13 designate thicknesses of the respective lens components and the airspaces reserved therebetween, the reference symbols n 1 through n 7 denote refractive indices of the respective lens components, the reference symbols ν 1 through ν 7 represent Abbe's numbers of the respective lens components, the reference symbol f I designates focal length of the front lens group, the reference symbol f II denotes focal length of the rear lens group, the reference symbol 2ω represents angle of field and the reference symbol f BW designates back focal length at the wide position.

Claim 10

A wide-angle zoom lens system according to claim 1 having the following numerical data: ______________________________________ f = 1 2ω = 73.4° ______________________________________ r.sub.1 = 1.5607 d.sub.1 = 0.134 n.sub.1 = 1.80440 ν.sub.1 = 39.62 r.sub.2 = 0.5778 d.sub.2 = 0.293 r.sub.3 = -1.5359 d.sub.3 = 0.138 n.sub.2 = 1.79952 ν.sub.2 = 42.24 r.sub.4 = 2.6583 d.sub.4 = 0.006 r.sub.5 = 1.3427 d.sub.5 = 0.172 n.sub.3 = 1.72342 ν.sub.3 = 37.95 r.sub.6 = -1.9997 d.sub.6 = 0.034 ˜ 0.733 r.sub.7 = 1.6325 d.sub.7 = 0.140 n.sub.4 = 1.61484 ν.sub.4 = 51.17 r.sub.8 = -3.1941 d.sub.8 = 0.014 r.sub.9 = 0.7374 d.sub.9 = 0.172 n.sub.5 = 1.62374 ν.sub.5 = 47.10 r.sub.10 = 2.8402 d.sub.10 = 0.167 r.sub.11 = -1.3876 d.sub.11 = 0.123 n.sub.6 = 1.78470 ν.sub.6 = 26.22 r.sub.12 = 0.7343 d.sub.12 = 0.052 r.sub.13 = 2.7624 d.sub.13 = 0.069 n.sub.7 = 1.63930 ν.sub.7 = 44.88 r.sub.14 = -0.725 f.sub.I = -1.633 f.sub.II = 1.182 f.sub.BW = 1.344 ______________________________________ wherein the reference symbols r 1 through r 14 represent radii of curvature on the surfaces of the respective lens components, the reference symbols d 1 through d 13 designate thicknesses of the respective lens components and the airspaces reserved therebetween, the reference symbols n 1 through n 7 denote refractive indices of the respective lens components, the reference symbols ν 1 through ν 7 represent Abbe's numbers of the respective lens components, the reference symbol f I designates focal length of the front lens group, the reference symbol f II denotes focal length of the rear lens group, the reference symbol 2ω represents angle of field and the reference symbol f BW designates back focal length at the wide position.

Claim 11

A wide-angle zoom lens system according to claim 1 having the following numerical data: ______________________________________ f = 1 2ω = 73.4° ______________________________________ r.sub.1 = 1.5837 d.sub.1 = 0.069 n.sub.1 = 1.72600 ν.sub.1 = 53.56 r.sub.2 = 0.5654 d.sub.2 = 0.310 r.sub.3 = -1.4697 d.sub.3 = 0.067 n.sub.2 = 1.72916 ν.sub.2 = 54.68 r.sub.4 = 2.8766 d.sub.4 = 0.005 r.sub.5 = 1.2186 d.sub.5 = 0.190 n.sub.3 = 1.60729 ν.sub.3 = 49.29 r.sub.6 = -1.7873 d.sub.6 = 0.034 ˜ 0.777 r.sub.7 = 1.3587 d.sub.7 = 0.279 n.sub.4 = 1.60729 ν.sub.4 = 49.29 r.sub.8 = -1.8865 d.sub.8 = 0.014 r.sub.9 = 0.6446 d.sub.9 = 0.101 n.sub.5 = 1.61484 ν.sub.5 = 51.17 r.sub.10 = 2.3631 d.sub.10 = 0.107 r.sub.11 = -2.1009 d.sub.11 = 0.1837 n.sub.6 = 1.80518 ν.sub.6 = 25.43 r.sub.12 = 0.6389 d.sub.12 = 0.086 r.sub.13 = -78.4331 d.sub.13 = 0.077 n.sub.7 = 1.59551 ν.sub.7 = 39.21 r.sub.14 = -0.7442 f.sub.I = -1.633 f.sub.II = 1.182 f.sub.BW = 1.293 ______________________________________ wherein the reference symbols r 1 through r 14 represent radii of curvature on the surfaces of the respective lens components, the reference symbols d 1 through d 13 designate thicknesses of the respective lens components and the airspaces reserved therebetween, the reference symbols n 1 through n 7 denote refractive indices of the respective lens components, the reference symbols ν 1 through ν 7 represent Abbe's numbers of the respective lens components, the reference symbol f I designates focal length of the front lens group, the reference symbol f II denotes focal length of the rear lens group, the reference symbol 2ω represents angle of field and the reference symbol f BW designates back focal length at the wide position.